A mobile crushing machine transported to crushing sites or building demolition sites can self-propel within a site if it is equipped with Crawler type traveling components. Nonetheless, this crushing machine cannot self-propel to the construction site on a public highway and therefore, must be towed by a trailer to the site.
Usually, a crusher installed on such a mobile crushing machine has a casing having a feeding port for feeding materials to be crushed.
Sometimes, a larger crusher, that can easily crush large rocks, concrete or asphalt blocks, is required for improved crushing efficiency. However, an increase in capacity of a crusher requires an increase in capacity of its casing. This requires one casing to have a large height, which may exceed the height limit imposed for its transportation by a trailer. To meet the height requirement, the crusher must be adapted to separate into components. These components must be reassembled when they arrive at the site which is elaborate work, time consuming and undesirable.
In an impact crusher, materials to be crushed are struck by stroke plates of a stroke component driven by a revolving rotor followed by collision onto impact plates to which the materials fly due to the striking action of the stroke plates. The size of the crushed pieces are determined by the gaps between the stroke plates and the impact plates. Therefore, to obtain crushed pieces of a given size, it is necessary to precisely adjust and maintain a desirable gap between the stroke plates and impact plates by moving the impact plates. Accordingly, the crusher of the present invention preferably includes a gap adjustment device for adjusting the gap between a stroke component (stroke plates) and the impact plates.